Biomass feedstocks such as algae and cyanobacteria are highly sought after because of Their high reproduction rates and growth densities, but their high concentrations of O and N heteroatoms are problematic for biofuel applications. Mild upgrading processes are necessary for producing fungible fuels from these renewable sources. We developed a process to upgrade spirulina-based bio-oil from tail-gas reactive pyrolysis (TGRP), using a combination of catalytic hydrotreatment and purification of the upgraded product.. The TGRP bio-oil was distillated at high organic yields, and the,distillates served-as the feedstock for catalytic upgrading. Simultaneous hydrodeoxygenation and hydrodenitrogenation (HDO/HDN) was carried out in one step using a commercial ruthenium catalyst on carbon support. Using bio-oil distillates as feedstocks for hydrotreatment produced hydrocarbons at high space velocities: Reactor temperature was the critical variable, wherein the-optimal temperature compromised between excessive yields loss and catalyst inactivity: While the HDO/HDN product contained relatively significant amounts of residual O and N (similar to 1 wt % each), the remaining O and N-containing compounds were removed via single aqueous phase extraction with hydrochloric acid. The extraction step serves as a milder alternative to deep HDO/HDN processes that diminish final product yields.